In a gas welder such as the CO.sub.2 welder, as shown in FIG. 1, the tip and nozzle are functional parts. The filler metal wire is led through the hole of tip and atmosphere gas is supplied through the nozzle. Meanwhile, the tip and nozzle are made of copper or copper alloys which are superior in the thermal conductivity, as well as having a certain level of strength.
To look into the current problem, many free spatters are sticked to the inner wall and the mouth of nozzle to make a thick deposition as long as welding. The thick spatter layer was a cause of inefficient supply of gas, and it was difficult to be removed. And in case of the tip, on account of a trouble something like the arc, it stopped the filler metal wire feeding.
In that case, The welding operation has to be stopped and dressed the nozzle to remove the spatter layer, and coated a preventing cream on the mouth and inner wall of the nozzle to avoid the deposition of spatters. Meanwhile, in the case of the tip, the end of the tip is ground or cleaned. In a more severe case, the tip has to be replaced with a new one.